Relay.



E. H. JACOBS.

RELAY. APPLICATION man JUNE 2, m4.

Patented Mar. 12, 1918,

ullmmllmii I Witnesses:

\ w m P. w 00 at a m 8 N a 6 n P E M UNITED STATES PATENT OFFICE.

ERNEST H. JACOBS, OF SCHENECTADY, NEW YORK, ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

RELAY.

Specification of Letters Patent. Patented Mar, 12, .1918,

Application filed June 2, 1914. k Serial No. 842,347.

To all whom it may concern:

Be it known that I, ERNEST H. JAooBs, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Relays, of which the following is a specification.

My present invention relates to circuit opening and closing relays and more par ticularly to relays adapted for use in connection with electric power distribution systems and which cause the power circuit with which they are associated to be opened upon the occurrence of certain predetermined electrical conditions.

The object of my invention is'to provide a device which will afford protection. to alternating current electrical apparatus from any harmful results arising from a reversal of the direction of the energy flow in the circuit to which it is connected.

Many relays of the reverse energy type have previously been constructed which operated satisfactorily as long as the voltage and power factor of the circuit were maintained at substantially their normal value but which failed to operate whenever the reversal of energy flow was accompanied by abnormal power factor or voltage conditlons. One common form of reverse energy relay is the dynamometer or wattmeter type in which two relatively movable members are employed, one provided with a series or current winding and the other with a shunt orpotential winding. With such an arrangement when the energy flow in the circuit is reversed the two members tend to assume a different position with respect to each other. The torque between the two members, however, as they have heretofore been constructed, has not beensuflicient to cause the desired movement whenthe voltage applied to the potential winding dropped to a low value, or when there was a large phase difference between the current and the potential applied to the relay. To overcome these difliculties various compensating arrangements have been proposed for use in the external circuit of the relay. By a novel arrangement of the parts and ime provements in the organization of the relay itself, however, I have been able to provide a device which will operate satisfactorily under the most abnormal conditions of voltage and power factor which ordinarily occur.

vThe novel features of my invention are pointed out with particularity in the appended claims. The invention itself, however, will best beimderstood by referenceto the following description taken in connection' with the accompanying drawing in which Figure 1 is a vertical cross-section of one embodiment of my invention with the movable parts shown in elevation; Fig. 2 1s 'a horizontal cross-section taken on the line w-w of Fig. 1; Fig. 3 is a plan view with the cover removed, and Fig. 4 is a view similar to Fig. 3 of a modified arrangement of the relay contacts.

As shown in the drawing the relay comprlses two fixed current coils 1 and 2 and a pivotally mounted potential coil 3. The current coils are wound upon spools 4 of non-magnetic material of substantially rectangular form with the usual protective insulation members 5 and 6. The current coils are surrounded by a frame 7 which is preferably of iron or other magnetic material which serves as a protective covering and at the same time serves as a path for the magnetlc flux set up by the current in the co1ls. An a1r gap 8 is provided at the top of this frame to prevent the flow of excessive eddy currents therein. The two coils are separated by blocks 9 which may be fastened to the rame by screws 10 as indicated.

The potential coil 3 is wound upon a spool 11 which may be circular in form as shown and which is also provided with protective insulating members 12 and 13. A split ring 14: of iron or other magnetic material is also preferably inclosed within the coil to serve as a path for the magnetic flux. Covers 15 also of iron or other'magnetic material are shaft to make contact with the contact member 21 and thereby close the circuit of the trip coil of a circuit breaker or other desired apparatus. When energy is flowin in the desired direction in the circuit to w ich the relay is connected, the contact arm assumes the position shown in Fig. 3 and is also normally held in that position by the spring 22. When, however, there is a reversal of the direction of energy flow, the potential coil tends to rotate in the opposite direction and cause the contact arm 20 to make contact with the member 21. Electrical connection may be made with the contact arm 20 by means of a flexible connector 23. The contact members are protected from dust, dirt and mechanical injury by a casing 24 which is provided with a removable glass cover 25 to allow for inspection and adjustment of the contacts. This casing is securely fastened to the frame 7 and the entire relay may be fastened to a suitable support by bolts or screws passing throu h the holes 26 in the rear of the casing. T e terminal leads for the relay coils and for the trip circuit are carried out through the insulating bushings 27 in the rear cover and in the bottom of the casin 24 as shown.

The potential coi normally occupies a position substantially perpendicular to that of the current coils and when current passes through the coils it tends to assume a position parallel to the current coil. The placing of the coils in this manner assists in the development of the maximum possible torque between them, and by making the potential coil with a large numberofaturns, well spread out as indicated, and causing it to move within narrow limits, a large number of the turns will always occupy a position at right angles to the current coil and suflicient torque will be developed to hold the relay firmly in its extreme position. By the arrangement of magnetic material shown it will be seen that I have cut down the reluctance of the flux path and. thereby increased the flux and at the same time have omitted all magnetic material between the coils where it would divert a portion of the flux of either coil and prevent it from interlinking with the flux of the other coil. This device I have found will operate successfully under the most abnormal conditions of voltage and power factor which occur in the ordinary operation of distribution systems. Under severe short circuit conditions with a voltage as low as one per cent. of normal,

. it will operate with a current of less than ten times the normal current for full voltage operation.

In Fig. 4 I have shown a modified form of contact which is especially suitable where it is desired that the relay shall open a circuit at the same time that it closes another. In this case the contact arm 28, instead of being mounted on the shaft of the relay, is pivoted at the point 29. It is held firmly 1n the extreme position of its travel by a spring 30 which is fastened to the arm 81 which in turn is mounted on the shaft 17 ofv the relay. When the shaft rotates it carries the arm 31 past the pivot point 29 of the contact arm and the spring 30 carries the contact arm over the dead center and to the other limit of its travel. A suitable contact member 32 carried on the end of the contact arm bridges a pair of contacts 33 at either end of its travel and thus closes a circuit.

While I have illustrated onl a single embodiment of my device, it wil be apparent that many modifications thereof may be made without departin from the scope of my invention as set fort in the claims which follow.

What I claim as new and desire to secure by Letters Patent of the United States, 1s,-

1. The combination in a relay of fixed current coils, a movable potential coil within the current coils and at right lee thereto, and magnetic material surrouii ng the current coils and forming a part 0 tential coil being wound around a mova le of magnetic material which forms a pfi the magnetic circuit of the relay.

2. The combination in a relay of fixed rectangular current coils, a movable circular potential coil within the current coils and at right angles thereto, a framework of magnetic material surrounding the current coils on all sides and formin a part of the magnetic circuit thereof, sai framework being thickened at points opposite the potential coil and a movable rin of magnetic material within the potentizfi coil 3. The combination in a reverse ener relay of fixed current coils wound on of non-magnetic material, a framewo l li of magnetic material surroundin said coils on all sides, a potential c011 pivotally mounted within said current coils and at right angles thereto, said potential coil being adapted to rotate in one direction when energy flows through the relay in the normal direction and to rotate in the o posits direction when the flow of energy t ro gh the relay reverses in direction, said framework bein thickened at points opposite the potential coil, and a ring of magnetic material within the potential coil and movable therewith, said thickened portions of the framework and said rin of magnetic material making up a part 0% circuit of the otential coil.

4. The com ination in a reverse ener the magnetic circuit thereof, said relay of fixed current coils and a movab e the magnetic magnetic material surrounding the current i coils and forming a part of the magnetic circuit thereof and a ring of magnetic material within the potential coil and movable therewith, said potential coil being adapted to rotate within narrow limits in two directions, being normally held at the limit of its travel in one direction and being adapted to travel in the opposite direction when the flow of energy through the relay reverses in direction.

5. The combination in a reverse energy relay of a fixed current coil, a potential coil pivotally mounted within said current coil and at a right angle thereto, a framework of magnetic material surrounding the current coil on all sides and a split ring of magnetic material within the potential coil, said potential coil being adapted to rotate within narrow limits in two directions, being normally held by a spring at the limit of its travel in one direction and being adapted to travel in the opposite direction when the flow of energy through the relay reverses in direction, the coils and their magnetic circuits being so proportioned that sufficient torque will be produced under short circuit conditions to rotate the movable coil when the potential applied thereto is as low as one per cent. of the normal voltage.

In witness whereof, I have hereunto set my hand this first day of June, 1914.

ERNEST H. JACOBS.

Witnesses:

BENJAMIN B. HULL, HELEN Onrono. 

